Various emerging carbon capture technologies depend on being able to reliably and consistently grow carbon dioxide hydrate, particularly in packed media. However, there are limited kinetic data for carbon dioxide hydrates at this length scale. In this work, carbon dioxide hydrate propagation rates and conversion were evaluated in a high pressure silicon microfluidic device. The carbon dioxide phase boundary was first measured in the microfluidic device, which showed little deviation from bulk predictions. Additionally, measuring the phase boundary takes on the order of hours compared to weeks or longer for larger scale experimental setups. Next, propagation rates of carbon dioxide hydrate were measured in the channels at low subcoolings ( less then 2 K from phase boundary) and moderate pressures (200-500 psi). Growth was dominated by mass transfer limitations until a critical pressure was reached, and reaction kinetics limited growth upon further increases in pressure. Additionally, hydrate conversion was estimated from Raman spectroscopy in the microfluidics channels. A maximum value of 47% conversion was reached within 1 h of a constant flow experiment, nearly 4% of the time required for similar results in a large scale system. The rapid reaction times and high throughput allowed by high pressure microfluidics provide a new way for carbon dioxide gas hydrate to be characterized.The density-functional tight-binding (DFTB) formulation of the fragment molecular orbital method is combined with periodic boundary conditions. Long-range electrostatics and dispersion are evaluated with the Ewald summation technique. The first analytic derivatives of the energy with respect to atomic coordinates and lattice parameters are formulated. https://www.selleckchem.com/products/BEZ235.html The accuracy of the method is established in comparison to numerical gradients and DFTB without fragmentation. The largest elementary cell in this work has 1631 atoms. The method is applied to elucidate the polarization, charge transfer, and interactions in the solution.Ce-based intermetallics are of interest due to the potential to study the interplay of localized magnetic moments and conduction electrons. Our work on Ce-based germanides led to the identification of a new homologous series An+1MnX3n+1 (A = rare earth, M = transition metal, X = tetrels, and n = 1-6). This work presents the single-crystal growth, structure determination, and anisotropic magnetic properties of the n = 4 member of the Cen+1ConGe3n+1 homologous series. Ce5Co4+xGe13-ySny consists of three Ce sites, three Co sites, seven Ge sites, and two Sn sites, and the crystal structure is best modeled in the orthorhombic space group Cmmm where a = 4.3031(8) Å, b = 45.608(13) Å, and c = 4.3264(8) Å, which is in close agreement with the previously reported Sn-free analog where a = 4.265(1) Å, b = 45.175(9) Å, and c = 4.293(3) Å. Anisotropic magnetic measurements show Kondo-like behavior and three magnetic transitions at 6, 4.9, and 2.4 K for Ce5Co4+xGe13-ySny.In the one-dimensional description, the interaction of a solute molecule with the channel wall is characterized by the potential of mean force U(x), where the x-coordinate is measured along the channel axis. When the molecule can reversibly bind to certain amino acid(s) of the protein forming the channel, this results in a localized well in the potential U(x). Alternatively, this binding can be modeled by introducing a discrete localized site, in addition to the continuum of states along x. Although both models may predict identical equilibrium distributions of the coordinate x, there is a fundamental difference between the two in the first model, the molecule passing through the channel unavoidably visits the potential well, while in the latter, it may traverse the channel without being trapped at the discrete site. Here, we show that when the two models are parameterized to have the same thermodynamic properties, they automatically yield identical translocation probabilities and mean translocation times, yet they predict qualitatively different shapes of the translocation time distribution. Specifically, the potential well model yields a narrower distribution than the model with a discrete site, a difference that can be quantified by the distribution's coefficient of variation. This coefficient turns out to be always smaller than unity in the potential well model, whereas it may exceed unity when a discrete trapping site is present. Analysis of the translocation time distribution beyond its mean thus offers a way to differentiate between distinct translocation mechanisms.Ice III is a hydrogen-disordered phase of ice that is stable between about 0.2 and 0.35 GPa. Upon cooling, it transforms to its hydrogen-ordered counterpart ice IX within the stability region of ice II. Here, the effect of ammonium fluoride doping on this phase transition is investigated, which is followed for the first time with in situ neutron diffraction. The a and c lattice constants are found to expand and contract, respectively, upon hydrogen ordering, yielding an overall negative volume change. Interestingly, the anisotropy in the lattice constants persists when ice IX is fully formed, and negative thermal expansion is observed. Analogous to the isostructural keatite and β-spodumenes, the negative thermal expansion can be explained through the buildup of torsional strain within the a-b plane as the helical "springs" within the structure expand upon heating. The reversibility of the phase transition was demonstrated upon heating. As seen in diffraction and Raman spectroscopy, the ammonium fluoride doping induces additional residual hydrogen disorder in ice IX and is suggested to be a chemical way for the "excitation" of the configurational ice-rules manifold. Compared to ice VIII, the dopant-induced hydrogen disorder in ice IX is smaller, which suggests a higher density of accessible configurational states close to the ground state in ice IX. This study highlights the importance of dopants for exploring the water's phase diagram and underpins the highly complex solid-state chemistry of ice.Controlling energy transfer through vibronic resonance is an interesting possibility. Exact treatment of non-adiabatic vibronic coupling is necessary to fully capture its role in driving energy transfer. However, the exact treatment of vibrations in extended systems is expensive, sometimes requiring oversimplifying approximations to reduce vibrational dimensionality, and do not provide physical insights into which specific vibrational motions promote energy transfer. In this communication, we derive effective normal modes for understanding vibronically enhanced energy transfer in excitonically coupled aggregates. We show that the dynamics of the overall high-dimensional vibronic Hamiltonian can be better understood through one-dimensional Hamiltonians separable along these effective modes. We demonstrate this approach on a trimer toy model to analyze the role of an intermediate "trap" site in mediating energy transfer between electronically uncoupled sites. Bringing uncoupled sites into vibronic resonance converts the "trap" into a "shuttle" for energy transfer.